Machine for cutting leaf tobacco



may 25, 1965 H. WARD ,l85,196

United States Patent 3,185,196 MACHINE FOR CUTTING LEAF TOBACCO Harry Ward, London, England, assignor to Robert Legg Limited, London, England, a British company Filed Aug. 1, 1963, Ser. No. 299,276 4 Claims. (Cl. 146-119) This invention relates to machines for cutting leaf tobacco of the type in which tobacco leaves, or parts of tobacco leaves, are dropped through a feed area onto a slowly moving first conveyor belt which is substantially horizontal, or is inclined slightly, to form a loose mass on the conveyor. This mass is gradually compressed as it is carried on the first conveyor belt into and along a duct which becomes progressively shallower and terminates at a mouthpiece. The roof of the duct may be a second conveyor belt, which converges with the first at or close to the mouthpiece, or alternatively a series of rollers mounted transversely to the belt. The compressed mass emerges through the mouthpiece and is cut transversely into shreds by cutters. Usually the duct is contained between substantially parallel vertical side plates, these being part of the frame of the cutting machine.

In order that as uniform a cut as possible shall be obtained and that bruising of the leaves be avoided it is necessary that there should be uniform compression throughout the mass and that the leaves should emerge through the mouthpiece orientated such that their plane and the line of their stems are at right angles to the cutting path.

The leaves are thus fed through the feeding area with the stems aligned with the length of the first conveyor belt. However, if there is only very slight compression on the leaves then the friction between leaves at each side of the belt and the side plates of the cutting machine is frequently suiiicient to cause the formation of voids in the mass of leaves on the belt and also to destroy the orientation of the leaves. A compactor is therefore frequently used to overcome this.

A known compactor comprises a substantially vertical or near vertical plate or set of prongs which is made to vibrate about a horizontal pivot and is adjustably mounted transversely to the belt to be part of or form the rear wall of the feeding area. However, such compactors are not entirely satisfactory in that the orientation of the leaves is frequently upset and that pockets of low density may still be formed.

We have now found that much more uniform distribution of the leaves may be obtained if the compactor consists of a surface movable to assist passage of the tobacco towards the first conveyor and mounted at an obtuse angle to the direction of movement of the belt and transversely to the belt, such that the vertical projection of the surface is substantially coextensive with the feeding area. The obtuse angle to the direction of movement of the first conveyor at which the compactor is mounted is chosen such that the top level of the mass of the leaves is substantially horizontal.

Thus in a method according to the invention for shredding tobacco a tobacco shredding machine of the general type described is used, and the tobacco is fed into the duct from above over an area of a surface which is movable to assist passage of the tobacco towards the first conveyor belt and is mounted at an obtuse angle to the direction of movement of the first conveyor belt and transversely to the belt, at a rate such that the level of the mass of tobacco in the duct onto which the tobacco is fed is substantially horizontal.

It is found that the angle of inclination of the surface of the compactor to the horizontal is much less in a compactor according to the invention than in previously known compactors. For example, it may be of the order of 35 to the horizontal. To obtain optimum distribution of the leaves using known compactors it was frequently necessary for the plate or prongs to be vibrated through as much as 3 inches, or even 6 inches, with the result that small pieces of leaf were frequently pumped rearwards at the bottom of the mass of leaves on the belt, or caused to fall between prongs, if prongs were used. However, using compactors according to the invention only very small vibrations (if any) are necessary and so these difficulties are avoided.

The movable surface of the compactor is a vibratable plate or conveyor belt, which may be slotted, and which may be vibratable and movable at a uniform velocity towards the first conveyor belt.

In cases where the surface vibrates the vibration is orbital, as opposed to pivotal, although the surface may vibrate with any combination of vertical movement and horizontal movement in the plane of movement of the first conveyor belt.

The feeding area may be defined, for example, by a hopper mouthpiece or it may be defined by a traversing conveyor belt feed.

A compactor according to the invention may be used very satisfactorily if only parts of tobacco leaves, in particular the stems, are being fed into the cutting machine.

The accompanying drawing illustrates diagrammatically one tobacco cutting machine according to the invention.

Leaf tobacco is fed into the duct 1, which is enclosed by two vertical walls 2 and two conveyor belts, 3 and 4, over a feeding area which is shown in the drawing as being defined by the area of a mouthpiece 5 above the space. The tobacco is conducted by the conveyor belts, under increasing compression, to a mouthpiece 6 at which it is shredded by a shredder 7.

The wall of the feeding area remote from the mouthpiece is comprised by the surface S of a compactor 9. The surface 8 is a plate mounted at an angle of about 35 to the horizontal and is caused to orbitally vibrate over its whole area with a movement of about Ms of an inch and a speed of about 1,400 c.p.m. by a mechanism mounted on anti-vibration mountings (not shown) and including throw weights 10 clamped on a shaft carried in bearings mounted on a frame 11 and driven by a motor 12, also mounted on the frame 11. Instead of a plate, surface 8 may comprise a conveyor belt which is caused to orbitally vibrate and move towards the conveyor belt 3.

Leaf dropping into the feeding area is fed in a manner and at a rate of feed such that the level of the mass of leaves in the duct 1 is substantially horizontal. Thus uniform straight lay of the leaves leaving the hopper 5 is maintained as the fresh leaves settle onto the mass. The vibrator plate 8, in combination with the movement of the conveyor belts 3 and 4, causes the leaves to move in the direction shown by the arrows towards the mouthpiece 6 without the formation of any voids, and so the straight lay of the leaves is retained and uniform compression exists throughout the mass at the mouthpiece 6. In order to prevent leaves dropping down the conveyor 3 there is a flexible rubber tongue 13 between it and the compactor plate pressing against the conveyor and of dimensions such that it is always in contact with the conveyor.

Other forms of vibrator mechanisms include eccentric, cam hydraulic and pneumatic vibrators. Suitable anti-vibration mountings are rubber supports or springs.

I claim:

1. A tobacco cutting machine which comprises a shredder, a mouthpiece adjacent the shredder, a substantially horizontal duct leading to the mouthpiece and of progressively reducing depth, its base being defined by a first conveyor belt, a feeding area to the duct through which tobacco may be fed to the duct and a compactor a resilient tongue extending from the end of the compactor comprising a surface mounted at an obtuse angle to the nearest to the first conveyor belt. direction of movement of the belt and transversely to the belt such that the vertical projection of the surface is References Cited y the Examine! substantially co-extensive with the feeding area, and means 5 UNITED STATES PATENTS for imparting orbital movement to the surface.

2. A machine according to claim 1 in which the mov- Z103 9/37 Blakeney et a1 14686 2,275,103 3/42 Goooh et a1. 146-110 X able surface a Plate' 2 535 692 12/50 M 1' t 1 146 110 3. A machine accord to claim 1 in which the movable 0 ms 6 a surface is a conveyor belt. 10

4. A machine according to claim 1 in which there is SPENCER OVERHOLSER Primary Examiner 

1. A TOBACCO CUTTING MACHINE WHICH COMPRISES A SHREDDER, A MOUTHPIECE ADJACENT THE SHREDDER, A SUBSTANTIALLY HORIZONTAL DUCT LEADING TO THE MOUTHPIECE AND OF PROGRESSIVELY REDUCING DEPTH, ITS BASE BEING DEFINED BY A FIRST CONVEYOR BELT, A FEEDING AREA TO THE DUCT THROUGH WHICH TOBACCO MAY BE FED TO THE DUCT AND A COMPACTOR COMPRISING A SURFACE MOUNTED AT AN OBTUSE ANGLE TO THE DIRECTION OF MOVEMENT OF THE BELT AND TRANSVERSELY TO THE BELT SUCH THAT THE VERTICAL PROJECTION OF THE SURFACE IS SUBSTANTIALLY CO-EXTENSIVE WITH THE FEEDING AREA, AND MEANS FOR IMPARTING ORBITAL MOVEMENT TO THE SURFACE. 